The present invention relates to a composition for dyeing keratinous fibers, in particular human keratinous fibers, comprising, as oxidation base, at least one compound of formula (I), defined below, which can be referred to, for convenience sake only, as an amino acid derivative substituted on an amino group by a group with an aromatic nucleus, to a dyeing process using such a composition and employing development by an oxidizing agent and to compounds of formula (Ixe2x80x2), defined below, which can also be referred to, for convenience sake only, as amino acid derivatives in which an amino group is substituted by a group with an aromatic nucleus.
It is known to dye keratinous fibers, in particular human hair, with dyeing compositions comprising oxidation dye precursors comprising xe2x80x9coxidation basesxe2x80x9d, in particular ortho- or para-phenylenediamines and ortho- or para-aminophenols, as well as couplers, also known as coloring modifiers, more particularly aromatic meta-phenylenediamines, meta-aminophenols and meta-diphenols, which make it possible to modify and to enrich with highlights the xe2x80x9cbasexe2x80x9d colorations obtained with the condensation products of oxidation bases.
In the field of oxidation hair dyeing, it is essential to have available oxidation dye precursors having a high dyeing power, in order to allow the formulator to create a broad palette of shades. Furthermore, it is also important for the oxidation dye precursors to have a high dyeing power at neutral pH in the region of 7 rather than at basic pH (pHxe2x89xa79), in order not to damage the keratinous fiber and to reduce irritation to the scalp.
It is as a result of much research that the inventors have discovered that it is possible to obtain intense natural shades on keratinous fibers, in particular at a pH in the region of neutrality, by using, as oxidation bases, compounds of the formula (I) set forth below which can also be characterized as amino acid derivatives substituted on an amino group by a group with an aromatic nucleus.
The subject-matter of the present invention is thus an oxidation dyeing composition for keratinous fibers, in particular for human keratinous fibers, such as hair, comprising, in a medium appropriate for dyeing, as oxidation base, at least one compound having the formula (I): 
in which:
n is an integer ranging from 0 to 11;
R represents a hydrogen atom, an amino radical, a saturated or unsaturated, linear or branched, C1-C6 alkyl radical or a radical chosen from: 
Rxe2x80x2 represents a saturated or unsaturated, linear or branched, C1-C6alkyl radical;
nxe2x80x2 is an integer ranging from 1 to 6;
X represents an aromatic group with one or two rings, wherein said ring or rings may comprise at least one heteroatom chosen from S, N or O; and further wherein said ring or rings are substituted, wherein at least one substituent on said ring or rings is an xe2x80x94NHRxe2x80x3 group or an xe2x80x94OH radical in the para or ortho position on the aromatic group X with respect to the xe2x80x94NHxe2x80x94 group, wherein Rxe2x80x3 denotes a hydrogen atom or an optionally hydroxylated, saturated or unsaturated, linear or branched, C1-C6 alkyl radical,
or an acid addition salt thereof,
with the proviso that compounds in which n=0, R=H and X is a 4-hydroxyphenyl radical are not included within formula (I).
The compounds of the formula (I) can be optically active isomers or mixtures of such isomers.
The novel dyes thus obtained make it possible to obtain strong and non-toxic natural colorings at neutral pH in the region of 7.
These novel dyes, in addition, exhibit good resistance to light, washing, bad weather, perspiration and the various treatments to which hair may be subjected.
Another subject of the invention is the ready-for-use dyeing composition comprising at least one compound of formula (I) as defined above, as oxidation base, and at least one oxidizing agent.
The invention is also targeted at a process for dyeing keratinous fibers, in particular human keratinous fibers, such as hair, which involves applying, to these fibers, at least one composition (A) comprising, in a medium appropriate for dyeing, as oxidation base, at least one compound of formula (I) as defined above and in developing the color in alkaline, neutral or acidic medium using an oxidizing agent which is added only at the time of use to the composition (A) or which is present in a composition (B) applied simultaneously or sequentially in a separate fashion.
Another subject of the invention is multi-compartment dyeing devices or kits, the first compartment of which comprises a composition (A) comprising at least one compound of formula (I) as defined above as oxidation base and the second compartment of which comprises a composition (B) comprising an oxidizing agent in a medium appropriate for dyeing.
A glycine derivative, namely N-(4-aminophenyl)glycine, is known in thermography as transfer reagent in a duplication process disclosed in French Patent FR-A-1,506,081 and in photography according to Patent GB-A-1,227,395 or Patent Application JP-A-02068546.
Another subject of the present invention is compounds of formula (Ixe2x80x2): 
in which:
n is an integer ranging from 0 to 11;
R represents a hydrogen atom, an amino radical, a saturated or unsaturated, linear or branched, C1-C6 alkyl radical or a radical chosen from: 
Rxe2x80x2 represents a saturated or unsaturated, linear or branched, C1-C6 alkyl radical;
nxe2x80x2 is an integer ranging from 1 to 6;
X represents an aromatic group with one or two rings, wherein said ring or rings may comprise at least one heteroatom chosen from S, N and O; and said ring or rings are substituted, wherein at least one substituent on said ring or rings is an xe2x80x94NHRxe2x80x3 group or an xe2x80x94OH radical in the para or ortho position on the aromatic group X with respect to the xe2x80x94NHxe2x80x94 group, wherein Rxe2x80x3 denotes a hydrogen atom or an optionally hydroxylated, saturated or unsaturated, linear or branched, C1-C6 alkyl radical, with the proviso that said ring or rings are not substituted by any nitro groups,
or an acid addition salt thereof
with the further proviso that compounds in which
n=0, R=H and X is a 4-aminophenyl, 4-hydroxyphenyl, 3-hydroxy-2-pyridyl or 4-hydroxy-3-pyridyl radical;
n=0, R=xe2x88x92CH3 and X is a 3-hydroxy-2-pyridyl radical; and
n=0, R=xe2x88x92CH2OH and X is a 3,4-dihydroxy-6-methylphenyl radical
are not included within formula (Ixe2x80x2).
These compounds of the formula (Ixe2x80x2) can be optically active isomers or mixtures of such isomers.
In the formula (I) or (Ixe2x80x2), X preferably represents a phenyl or pyridyl ring substituted by an amino group xe2x80x94NH2.
The preferred compounds of the formula (Ixe2x80x2) are:
Nxcex5-(4-aminophenyl)-L-lysine;
Nxcex5-(4-amino-2-pyridyl)-L-lysine;
Nxcex1-(4-aminophenyl)-L-lysine;
Nxcex1,Nxcex5-di(4-aminophenyl)-L-lysine;
N-(4-aminophenyl)-L-serine;
6-[N-(4-aminophenyl)amino]caproic acid;
xcex1-N-(4-aminophenyl)amino-xcex5-caprolactam; and
their acid addition salts.
The acid addition salts are preferably chosen from hydrochlorides, sulphates, hydrobromides and tartrates.
The preferred compounds of the formula (I) for being used in oxidation dyeing according to the invention are: Nxcex5-(4-aminophenyl)-L-lysine, Nxcex5-(4-amino-2-pyridyl)-L-lysine, N-(4-aminophenyl)glycine, Nxcex1-(4-aminophenyl)-L-lysine, Nxcex1,Nxcex5-di(4-aminophenyl)-L-lysine, N-(4-aminophenyl)-L-serine, 6-[N-(4-aminophenyl)amino]caproic acid, xcex1-N-(4-aminophenyl)amino-xcex5-caprolactam, and their acid addition salts.
The compounds of formula (I) or (Ixe2x80x2) are prepared according to the following procedures, depending on whether they are lysine derivatives, glycine derivatives or other derivatives, such as w-amino acids and lactam derivatives.
General Procedure:
10 g (54.75 mmol) of L-lysine monohydrochloride are dissolved in 44 ml (2 eq) of a 10% aqueous sodium hydroxide solution and 120 ml of water in a 500 ml three-necked flask equipped with a thermometer and a 50 ml dropping funnel. A solution of 6.8 g (0.5 eq) of copper sulphate pentahydrate in 40 ml of water is introduced into the reaction mixture, followed by 4.6 g (1 eq) of sodium hydrogencarbonate and 40 ml of ethanol. A solution containing 1 equivalent of 4-fluoronitrobenzene or of 2-chloro-5-nitropyridine in 40 ml of ethanol is prepared and then run dropwise onto the homogeneous mixture. After heating for 6 hours at reflux, the reaction mixture is cooled and then filtered. The green-yellow precipitate, corresponding to the final product in the form of a copper complex, is washed with water and with acetone and then dried in an oven under vacuum. To remove the copper, x mol of complex are treated with 2 eq of thioacetamide at reflux of water. After having removed the copper sulphide by filtration on paper, the filtrate is cooled in order to obtain, by crystallization, the expected final product.